3-PUU并联坐标测量机中滑块运动误差是关键的误差源，必须予以修正。定性分析滑块运动误差对万向铰链中心位置和光栅读数的影响，建立基于滑块运动直线度的仪器误差模型。将双频激光干涉仪获取的运动直线度误差数据进行拟合，并以此为基础定量分析此项误差对仪器总误差的贡献，为完成该项误差的修正奠定了基础，这对于仪器总体精度的提高及后续测量机结构参数的标定具有重要的意义和价值。

Sliders motion error is the key error source of 3-PUU parallel coordinate measuring maching(CMM), which must be corrected or compensated carefully. The influence of sliders motion error on ball hinge centre position and linear grating reading are discussed and evaluated qualitatively, then the error model including slider linear motion error is established, slider motion straightness error data of 3-PUU CMM are captured by dual frequency laser interferometer. Through theoretical calculation, the contribution of sliders motion error on the instrument total error is derived and provided quantitatively with obtained experimental data，which paved the way for error correction. The work will be very useful for the following instrument accuracy calibration. Especially, it will improve the calibration accuracy on the parallel mechanism structure parameters.